Optical frequency domain reflectometry with high sensitivity and resolution using optical synchronous detection with coded modulators

A new optical frequency domain reflectometry (OFDR) method is demonstrated. Two broadband, coded, travellingwave electro-optic LiNbO3 modulators are used over a 25.6GHz frequency range, one as a source and the other as an optical synchronous detector. A 4 mm resolution in fibre is achieved, along with a dynamic range improvement of ⋍18dB (optical) over previous OFDR results.